SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be322f5d83b4f338f83876cbc6e369f4bcb58d903d7156379b277d320a2bd253' 
  AND token = 'xhyCsWGmVfFJpcRjhac9LDZpPYlOyji9/MuC28wtWho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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