SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf2179e4838abc34987420a069c500a0d5085b7487d0a9e5d402f2c31a6c2d35' 
  AND token = 'e+MDWGA6Hzk//bJAPvhHkz4WC9Yu5vFkzZeq5rKzNew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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