SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a830f77fc22d0a9d9924e12f683454478f8b28ffee4cd84600e88721ce5158c' 
  AND token = 'LoaB8XprpBMZqOxOLUvKgHN0KM/jhpw3D925MAq7Cj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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