SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20d385802c90ccd654f1f88ea131d4a62fe5bbbda7bd15bcf47c842ab4428b09' 
  AND token = 'AYdMOjqqlDZgjW9YBHSjrORj5+eKqJd9eFXa71AXHoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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