SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd71914c4a875bb5f87a84851069fb955dd3a95192662e00d1b05b69e91a05b35' 
  AND token = 'wrhkV7eDFRBFCZbBNaXSzIgognB3iw74iKO0l41CMes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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