SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35bf0ab317b230d2257d167ae69e9cae76f77fc3c67fdaf134ba9517aaaca9b' 
  AND token = 'u8cTe3mVEyV567aFuJjMjvlpe9/rypYcLXHffNsgulE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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