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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e63d72c1b5ad39ae8d7bcd2d76eaf68ac0e4b05c038bfa3c36f187413af7896e' 
  AND token = 'q9LUC5s8JHdnzzjJzVcA1Ry96cpVEIurzs6ZAsiZt+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}