SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0c349016fe537e23bdfdc2165caee720655b3c487611671cccf280b7ae51609' 
  AND token = '1PNBr5nmjdyJwjWR7vQFHE4/8XhLqZsIYIt1jH4omZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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