SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8278a41a8f60e5d353212c546fe52dc9f78ef4fc636138ad4981e4fddca6da5c' 
  AND token = 'lh2HvGYW/9jRYfN7Ouvy96BXaNJVkYB2KPJdEZmXPSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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