SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bc82e36d4743acf2253a4d4deab111d04620445821c0087184cf7051d5784ab' 
  AND token = '2zmZ+FqBVIlVhH2tHGBP6PqfXQSJUgsvDnB7Wowna1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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