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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4a81a0534f7849980b21b21151f63278e14b0d0aca42b8f146cdfeda36003c5' 
  AND token = '46I02IKFz1T0cEb6eUVCpbbKl18Np6JjiUki09iykss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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