SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eb759bb4b0193d67ddd68a7042b73bf18812be340736a19356259a6ca604fbd' 
  AND token = 'ZwgTkMh+wZmW2nF1jlINzljyBRbKZHlG/8POe/XFN7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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