SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '803c7678d5c1f4542a319cf96dab2bad2f391fe290e1268afb243f68e0895990' 
  AND token = 'YF2gpJ6TcJ1OYd9DryOnpdZ8FBv4jF6RVcq71fwbIo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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