SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f42d30bdbaeb1c9f737665489fedac24f491d33a1e38112554ad98636b59751' 
  AND token = 'fYNwSEMF9od9cgtKxumdlv+N4iLcfn1HHb8pUDzKTkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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