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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8f8dc3f89dfffcae5e01c5ea2c3766e01b4b4f7b862b717ef0ad3410783b1b9a' 
  AND token = 'U7r/odAS+FUsizopOrth46lRaq5dPsnHd2tw+ZV0HI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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