SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0d4abfeb24bc31c12b0fdc17b0aa94fe2269df7e19d183bf1f8c835307e3717' 
  AND token = 'vAQGqA5n/fTZU9FgyxVnsXUs2n7ApwLxhCH+mZSVrwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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