SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cffcc612b400b239d0e54ebd3bf6270702821fb67188c423674115e0909c573' 
  AND token = 'VhzD1Kp9SvlLnacCVg6ZCnPehrWB+hQmbAXr0ZvcG1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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