SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468cdae2e0661fd07ced6596fa2d235a5a8eb3e2bfbdd782027e99deeb0bc836' 
  AND token = 'An1dYJ8Ymmit9HfEnOWpVW9XPoaSxAncqo4UpWDkpzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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