SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e0ab8a840c02e24af806ce46d78b4c3cecc200887198852638072cc90666777' 
  AND token = '7AM915CiNOGQrRp1DqUBHNjeu0wXY+NM8dH2HucKeq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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