SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2a60cefadbb03c9ebced7338293707c3a2a59104730906d30c9e3ea024742fe' 
  AND token = 'rehD3gN0dmYGe+HP6SdyEeIJ6MxLjMtfy7miuwvdpRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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