SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ffe22d548c9f729f6551e94f7cef6c8c792c75471e57576099447e61606c474' 
  AND token = 'x4zSfkIslJkIbzTytN2p198GRRWBHD3Psw+1aDVcqgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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