SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd654b1991a0a138070fea9d78861ab2b474ca92ecba2d597af20c62343598f95' 
  AND token = 'IsBlmoH4sP7iphzGDYGOxgNO8X1PAo9thqpu/eTnrgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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