SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a0ad977b8cfdcd91ceb3e504e611860b22337ac946801dcc52db1f07ccd0da' 
  AND token = 'lxTC9YSdayQLrkTuYmNqCrMgQfoY8PARjXz/zsT9nWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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