SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78599f8a5c548365d4f242a2881d807390e0fd85e43da29ceef1d300ad48c78' 
  AND token = 'XEDl3vLhbAkD7vEJK/xJuxWJY8knMyhV+qIZUChht6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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