SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e04f3d0d12c10cf4382213a0091779f5d75292f759025062891f90e9475b90e' 
  AND token = 'ARnnUduKwA2RxWTwt7sL1OU9oQcnWgaDmj+vYepzr20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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