SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '391f59a37f606cd29473e9c4f4d142e49fd74ccf05e6292faa5d8787d7548092' 
  AND token = 'rUrtC1O10mm4WFtLe6FEvcAzOCLJrjHHySwb99bMb0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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