SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18cd186d2bd5cce56b79792e987fb2c24687142e94fec43fcb169c9eaf68739a' 
  AND token = 'D7UgjlZET8J5iX00Ty+hI6sn06Qz25x3KetOnXuFy34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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