SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fdf8b37656a2e802e33e7eaa3e369f50ab84e95a53afc06998616c2e609fb9d' 
  AND token = '5B13ZIrcsPlFbv4rEz7EMg020rZqCTO6yORfyq15h/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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