SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c62055f21b63f170217e1a4fbc1c47c2b794aa47a9ff34affedf271966c3fe' 
  AND token = 'iLNekP0l5DVN9N2MQXNKEuyBtkC486h+arRtd2CRVvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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