SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10a6f58cee738bc54cf475ffa54c6a4805b800d873a498b631390d4dd575dcc6' 
  AND token = 'vG1aqQJRJEoM2PwrE8k7rThW9ykpbd/p6KBT6S4iLpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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