SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5379898b8485942f589893d9acce4a718ad799c30027e82ad507c9f783c595ca' 
  AND token = 'k8IE7hLiL2Gyv6zh/5tRst+Peu3ZddJGAp3P103ZvIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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