SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a38de4db156deb00779107bfe45870b61fe6fff3351e0a6dee1582da42955a' 
  AND token = 'V8pZcdWCmfZ5w5AnuCmZhJiboMwdY8vcsLofScS9J24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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