SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a542321d0c0bdf8190207a9f064084840720f4e55fd6094ccd43c45996d827d1' 
  AND token = '1ac7yyRD8jkCrzkqBLeqj2GzYdw/FdfuCuYJTgav8JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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