SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a94f1ae4d6680b303f6c40b47a06ef9138fa8d28451ed813b2635660d99e13' 
  AND token = 'UHeX5o0jEFAu75SyiVdLVXBN/DW4TfZbIsbTGrHFNqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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