SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e55b44ce3593c255b5c22a492ba094d2ec59301eb3ab4dc94e35a06cdbd0f325' 
  AND token = 'hHMInAsO9I+FOhsnbNtwX1FZxnLCnsi6oQf1O4rIIkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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