SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be4a8d0f7d6796619663156df802f8d85dad9cf8443131894d957cdddf745d5a' 
  AND token = 'Gw5hjXSJccXfpstgaBPNTiWmUemQay7yjjtOFzaQEZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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