SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63f68a3bba0e5cc413d789303baa63ddaaa11fc8fb1a598f015e9562bd6c3289' 
  AND token = 'RQXcVnNRDzEimvc8iwQHCrcsLNd+XVB79irVrA+TmY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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