SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '309f5e3d7dcb4112ec6d306706791c98f43dedd02e39fd903ff6dfa7fb33d2d0' 
  AND token = 'u1KULySlJ3SzMeR2U26/9WHHdeo+YNaUJgEP7DQMP8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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