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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d168d05816cf20d5b9f6bdb83bbc93bb46e6abbf0393f7a8aca6a170adfd1c' 
  AND token = 'H2Uo0qr7EpdjggimyMOln+GYVFGV+vEzNKQ0iK7v6EU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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