SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '558b29c3b8093284382ea5b25291152bc94a377a50b74030f595f9e9360af765' 
  AND token = 'MRIc+7GYg1S+wtxVxuQVhwIdRjAj5ug9pQvwe1wzONw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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