SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5d8d15e404a83d766764a28608f06f524cb7844a4195f46efdb29a22e1ff384' 
  AND token = 'rP+ksLrK3ARjCg0F8mhgNL3hhz8Jc9NtTzM3AiiDZ4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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