SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86b772d8cfd939be214699238959cc4973b1f82c69acf851619e808251782ea' 
  AND token = 'sbUmWYK5iqxJGJRU/8R7dzfdqqhSCGYiMUDzKLw0KiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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