SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c14da3b49633ecccfbb41fea12ce5db935811d96365fd1cf194f0c2a2b0adcb4' 
  AND token = 'uc/pOM0gPl694s3nIUxs7V9NE/cVk95LujmKuAdGSQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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