SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd6d51f19ffeaa7708dfa0425a05a77ec34c67d778a5c4d744c438a7bcf5a403' 
  AND token = 'aZO/c/S/PTv1+mJUBSEHFVlillx22nsB9MlDfIOJYu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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