SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '443f48e331d1a0b556d36655cfa4a1d199db2ea308b8a5e288009a1dd652cf8f' 
  AND token = 'a5s735qh8UXlfhBrmuOWAYKko6yajFNcIGHGImPtCT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}