SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f5b0e4a5b9d199669e65632ce0146c294dd227e07a638feae4655379671f0b7' 
  AND token = 'PsRCHQoPQJCwzj1jdaOXeXtg5RvizXuhixHyAYUUSOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00093

JSON explain

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