SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69fb2520367fbea503e4c75d219ddb42661c13234767a8bc58c51a0649241e36' 
  AND token = 'tUzyrnkb1NqCrsPpbSXVJVZBcc+Tz0WSw/gXSYnilVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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