SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '274077c2f736c4c4737a85d8d2c099d6f8708d3e0cfc6d22eb5a816620d25a98' 
  AND token = 'xCNcBvbNSweO2HnskxXDwSFOVnP9GMFUKLTYluhgHKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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