SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5449188fe87e2416a09d927637927310f4f83ee2ad5561719037577d51bab3f' 
  AND token = 'kf+4PhU1Q+3qEUUeNOjN7TUtOTJWfoHvofTJw3NQbeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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