SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ed6515822167cb2494d92630526b29ea235a44e2dcc686e0aa7b12deef1712' 
  AND token = 'YR8PF+uQAqG2wiJvynZOAXn/uObp4hoPvMFgBD8ks2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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