SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e512194f36b4c3912e57486e3f9b7ccf7718fddc7e83092ce4f33b45eda13a52' 
  AND token = 'tnQKCLrqCUMKgtonqWkQAhqjNCWVAiYfwH6jLk1rgZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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