SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd755c40ed617104dcd157de97fff369337c4d689cf5a27322de4a16ba4772fdb' 
  AND token = 'ZFXGxZO3J10XmfINZORAZPgJJslczxgjLTi4Ds/x7zQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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