SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387a1a5daa4649f35605c836657c9a7339504a5826da31f6a8650ebac3cb5787' 
  AND token = 'TUYO1OgbxGe/NEYso2qhJ7Ch0Y0cSsQkAPf8uc33xu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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