SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aedf0151a47cbc43f177a5c38a01e7c75e0a4a079c1c1c46e89bf535089d735' 
  AND token = 'akw0gIGhRTlOzbTwAgNq55SVyuwiRYY868kTmgI52Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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