SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25712b1b88ada0f8b0951307f475a27aaa64f157a535fbc316facb6deea9a12' 
  AND token = 'nFY6NJKaOqUoby8G3q1ERcCpXK9Vk9I+0LNLZZrepi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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