SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e720e1e15399a4818f2e9cce0f3e9ce52a966e79311b9b7c96463edee26c9cbd' 
  AND token = 'cleVbeRFIVbGYt1b7S6m8wmNYoTtJmYaNKsIZxAiEZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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