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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c762cb081e0849543978f3c124a11fd078c447c8f19ed69ef05c15d18c82f60c' 
  AND token = 'mgbAbB6AMiFBCvMh9TIAURqEr/YQWNaoTBJa2CX1EzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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