SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3508924eecbaa696865366716d795fc4e17e95188e11429b1136c4db86e2f60a' 
  AND token = 'uUAaFqBZ6NWgQWo5xvfSvPuSSRGQkTcfTcEXBXnTY34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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